Corrosion inhibiting resin-bonded solid film lubricant



United States Patent 3,314,885 CORROSION INHIBITING RESIN-BONDED SOLID FILM LUBRICANT George P. Murphy, Jr., Rock Island, Ill., assignor to the United States of America as represented by the Secretary of the Army N0 Drawing. Filed Apr. 15, 1964, Ser. No. 360,150

4 Claims. (Cl. 252-45) The invention described herein may be manufactured and used by or for the Government for governmental purposes without payment to me of any royalties thereon.

The present invention relates to a solid film lubricant and more particularly to an improved resin-bonded solid film lubricant the qualities of which combine to provide good corrosion inhibiting properties with excellent wear life, such as disclosed in the United States Patent Number 3,223,626, issued Dec. 14, 1965, jointly to F. S. Meade and applicant herein, and assigned to a common assignee.

Efforts are constantly being made to produce a solid film lubricant for protection of metals which will provide long wear life as well as good corrosion protection. As pointed out in the above identified patent application, there are some excellent resin-bonded solid film lubracants on the market for preventing corrosion which contain a common ingredient graphite because of its beneficial synergistic effects when used with molybdenum disulfide. However, the presence of graphite in such lubricants has been found to accelerate-corrosion rather than protect against it. While the'lub'ricant suggested 'by the above identified copending application offers an excellent substitute without employing graphite as one of itsingredients, experimentation. has resulted in further improvements which are presented herein.

Therefore, a primary object of the present invention is to provide an improved corrosion inhibiting resin-bonded solid film lubricant.

It is also anobject of the present invention to provide a resin-bonded solid film lubricant having a long wear life as Well as an excellent corrosion inhibiting quality.

. Furthermore, it is an object of the present invention to provide a'resin-bonded solid film lubricant which avoids the use of graphite and eliminates the harmful effects incident thereto. it

Still another object of the present invention is to provide an improved corrosion inhibiting resin-bonded solid film lubricantwhich is relatively simple to prepare .and which isihighlyegtfectivev as ,a corrosion inhibiting composition.

In accordance with the present invention, an improved resin-bonded solid film lubricant is provided by admixing a quantity of dibasic lead phosphite with an epoxyphenolic resin system, antim ony trioxide, molybdenum disulfide, magnesium bentonite, and diethylene dioxide.

The'novel features of the present invention, as well as additional objectsand advantages thereof, will be understood better from the following detailed description, illustrating the present invention by the following preferred example of a composition prepared in accordance therewith.

i Example 1 Percent by wt. Epoxy-phenolic resin system (35% solids) (solids:

Antimony trioxide, powdered, ACS grade 6.2 Molybdenum-disulfide, natural 17.4 Dibasic leadphosphite 4.1 Modified magnesium bentonite 0.5 1,4-diethylene' dioxide 36.4

ice

Alternative lubricants may be prepared consisting of the following compositions.

Example 2 Percent by wt.

In the above identified examples, the epoxy-phenolic resin system which has been selected by preference is that known in the trade as Epon Resin Formulation YP-IOO prepared by Shell Chemical Corporation. The ingredients of this resin system are composed of 35 percent solids and 65 percent solvent taken from the following compositions:

Percent by wt.

Epon resin 1007 73.1 General Electric resin 75108 24.4 Silicone resin SR-82 1.0 Phosphoric acid 1.5

Total solids 100.0

Ethyl alcohol 25.0 Methyl ethyl ketone 15.0 Toluene 50.0 Pine oil 10.0

Total solvent 100.0

In the above resin system, Epon resin 1007 is a commercial product made by Shell Chemical Company. Epon resin 1007 is a solid high molecular weight polyglycidyl ether of 2,2-bis(4-hydroxyphenyl) propane having the following properties:

Melting point 112128 C.

Mol weight About 2900.

Epoxy value About 0.06 eq./ g.

It is believed to have the general formula wherein R is the portion of the 2,2-bis(4-hydroxyphenyl) propane molecule remaining after removal of the two OH groups and n is about 9. General Electric resin 75108 is .a commercial product made by General Electric Company. It is a resin of the phenolic type with the following characteristics: viscosity at 25 degrees centig rade, 2000-4000 centipoises; color, clear, dark brown; flash point, closed cup, over 200 degrees Fahrenheit; free Water content, O-2 percent. For composition of General Electric resin 75108, reference is made to US. Patent 2,579,330, wherein the resin is a mixture of the allyl ethers of mono-, di-, and trimethylol phenols, the last predomiating. This resin is characterized by the structure of the adicals set forth in column 1, lines and 30, and the lethod of preparation is more particularly described 1 Example VII, column 5, of the patent. Silicone resin R82 is a commercial product made by General Electric Company. It is a resin'of the silicone type with he following characteristics: specific gravity at 25 de- ;rees centigrade, 1.19; color, maximum, 6 (Gardner); hard solid compatible with a wide variety of compounds; oluble in xylene and toluene. For composition of Silione resin SR-82, reference is made to U.S. Patent 2,258,- .22, wherein the resin is characterized by the structure et forth in column 1, line 20, and the method of preparaion is more particularly described in column 2, line 45, hrough column 3, line 67, of the patent.

Antimony trioxide is an oxide from the class of in- )rganic metallic oxides. While other metallic oxides night be used, antimony trioxide is preferred since other netallic oxides from this class are not found to be as :ffective. The modified magnesium bentonite is that :nown as Bentone 38, made by Baroid Division of Naional Lead Company. This is a finely powdered mate- 'ial made by replacing the inorganic cations of a clay nineral lattice with organic cations. The solvent p-di- )xane is technically known as 1,4-diethylene dioxide, iOl'Ilfitll'1'16S called para dioxane. Although other solvents :an 'be used, such as a mixture of equal parts of diacetone and xylene, the results obtained are not considered to be is satisfactory. Therefore, it is preferred that p-dioxane 36 used as the solvent.

The ingredients set forth in the above formulations were prepared by adding them in the following order to a one gallon friction lid can containing 20 one-half inch diameter steel balls:

(1) Epoxy-phenolic resin system;

(2) Antimony trioxide;

(3) Molybdenum disulfide;

(4) Dibasic lead phosphite;

(5) Modified magnesium bentonite; and (6) Diethylene dioxide.

There was substantially no time lag between the addition of each ingredient. The can was sealed, shaken by hand for approximately one minute and then rolled for four hours at room temperature. The formulation was prepared at room temperature and no heating was required.

It is always considered best practice to steel grit blast or sand blast steel surfaces prior to zinc phosphatizing. All test specimens were steel grit blasted prior to zinc phosphatizing. Inasmuch as the formulation contains a relatively high percentage of solvent, it was necessary to dip each specimen three times in order to obtain a coating thickness of 0.0004 to 0.0007 inch. The dipping procedure was accomplished by suspending the specimen in the lubricant for a period of 5 seconds for each successive dip, removing it after each dip and allowing it to dry for ten minutes after each of the first two dips before proceeding with the next dip. After the final dip, the specimen was allowed to dry for one half hour followed by oven curing to bake the resin at 400 degrees Fahrenheit for one hour.

Coatings provided in accordance with the above described formulations were tested and found to provide excellent wear life as well as corrosion protection when applied to zinc phosphatized steel as well as anodized and sealed aluminum. For this purpose, test specimens coated with these lubricants consisted of American Iron and Steel Institute, also referred to herein as AISI, C1020 steel panels /a x 2 x 3 inches for the salt spray cabinet exposure tests, and standard Falex test specimens for the wear tests. The Falex pins were made from A151 3135 steel hardened to Rockwell B87-90. The V-blocks were made from A181 1137 steel with a hardness of Rockwell C20.

In order to demonstrate the effectiveness of employing dibasic lead phosphite in the lubrication composition, specimens were tested using compositions made in accordance with the above described formulations and comparison made with a composition prepared in accordance with Example 2 set forth in applicants copendin g patent application identified above. The results of this comparison are as follows:

Falex Wear 20% Salt Life (in Spray (Hours minutes to failure) Example 2 of copending patent application dibasic lead phosphite) 365 24 Example 1 (above) 500 1'20 Ex unple 2 (above) 168 Example 3 (above) 375 168 It is a white crystalline solid with a molecular weight of 743, a specific gravity of 6.94 and a lead content of 90.8 percent.

It will be appreciated that certain changes and variations may be made in the specific formulations described herein without departing from the scope and the prodnot provided by the present invention. For example, Examples 2 and 3 outlined above demonstrate that while they offer some degree of wear life and corrosion protection, the preferred embodiment represented by Example 1 offers five times as long corrosion protection and increased wear life over lubricants which do not contain dibasic lead phosphite. Accordingly, depending upon the particular application of the lubricant, the composition of the present invention is susceptible of variation within the following ranges:

Percentages by wt. Epoxy-phenolic resin system (35% solids) (solids: 7 to 15.75) 20 to 45 Antimony trioxide, powdered, ACS grade 4 to '18 Molybdenum disulfide, natural 10 to 24 Dibasic lead phosphite 2 to 9 Modified magnesium bentonite 0.2 to 1.7 1,4-diethylene dioxide 20 to 45 Although the above constituents may be varied within the ranges indicated, it is recomended that care should be exercised in the ratio of antimony trioxide to molybdenum disulfide since this ratio is critical from the point of view of Falex wear life.

What is claimed is:

1. A composition for forming a solid film lubricant, which consists essentially of the following ingredients:

Percentages by wt.

Epoxy-phenolic resin system 35.4 Antimony trioxide 6.2 Molybdenum disulfide 17.4 Dibasic lead phosphite 4.1 Modified magnesium bentonite 0.5

and 1,4-diethylene dioxide 36.4

2. A composition for forming a solid film lubricant, which consists essentially of the following ingredients:

Percentages by wt.

Epoxy-phenolic resin system 28.5

Antimony t rioxide 5.2

Molybdenum disulfide 14.5

Dibasic lead phosphite 7.9

Modified magnesium bentonite 1.5

and

1,4-diethylene dioxide 42.4

3. A composition for forming a solid film lubricant, which consists essentially of the following ingredients:

Percentages by wt.

Epoxy-phenolic resin system 28.5

Antimony trioxide 5.7

Molybdenum disulfide 16.0

Dibasic lead phosphite 5.9

Modified magnesium bentonite 1.5

and

1,4-diethylene dioxide 42.4

4. A composition for forming a solid film lubricant, which consists essentially of the following ingredients:

Percentages by wt.

Epoxy-phenolic resin system 20 to Antimony trioxide 4 to 18 Molybdenum disulfide 10 to 24 Dibasic lead phosphite 2 to 9 Modified magnesium bentonite 0.2 to 1.7

DANIEL E. WYMAN, Primary Examiner. I. VAUGHN, Assistant Examiner. 

1. A COMPOSITION FOR FORMING A SOLID FILM LUBRICANT, WHICH CONSISTS ESSENTIALLY OF THE FOLLOWING INGREDIENTS: 